1. Field of the Invention
The invention relates to a semiconductor device and a method of manufacturing the same, particularly, a package having about the same outside dimensions as those of a semiconductor element packaged in it and a method of manufacturing the same.
2. Description of the Related Art
A CSP (chip size package) has received attention in recent years as a packaging technology. The CSP is a small package having about the same outside dimensions as those of a semiconductor element packaged in it. A BGA type semiconductor device has been known as a type of the CSP. In the BGA type semiconductor device, a plurality of ball-shaped conductive terminals made of metal such as solder is arrayed in a grid pattern on one surface of a package and is electrically connected to a semiconductor element formed on the other surface of the package.
When the BGA type semiconductor device is mounted on electronic equipment, the semiconductor element is electrically connected to an external circuit on a printed board by bonding the conductive terminals to wiring patterns on the printed board.
Such a BGA type semiconductor device has advantages in providing a large number of conductive terminals and in reducing a size over an SOP (small outline package), a QFP (quad flat Package) or the like, which have lead pins protruding from their sides. This BGA type semiconductor device is used as, for example, an image sensor chip of a digital camera mounted on a cellular phone.
FIGS. 13 to 15 show a method of manufacturing a conventional semiconductor device. As shown in FIG. 13, a semiconductor substrate is provided in which first wirings 53 are formed on semiconductor elements 51 with an insulation film 52 being interposed therebetween and a glass substrate 54 is attached to the substrate with an adhesive layer 55 so as to cover the first wirings 53. Second wirings 57 are further formed being connected to the first wirings 53 and extending onto the back surfaces of the semiconductor elements 51 with an insulation film 56 being interposed therebetween. Then, a process of forming slit groove G in the semiconductor substrate with a dicing blade is performed prior to separation of the semiconductor substrate into each of the individual semiconductor elements 51 along the border S (a dicing line).
Then, a protection film 58 made of a solder resist film is formed on the back surface of the semiconductor substrate including the slit groove G as shown in FIG. 14, and then conductive terminals 59 are formed through a predetermined process as shown in FIG. 15. Finally, the glass substrate 54 is separated along the border (called a dicing line or a scribe line) S, thereby completing semiconductor devices.
The relevant technique is described in Japanese Patent Application Publication No. 2005-72554.
As shown in FIG. 15, the conventional semiconductor device has low moisture resistance at a contact portion A of the protection film 58 made of hygroscopic resin and the adhesive layer 55, and it is likely that moisture or the like infiltrates between the adhesive layer and the glass substrate or the like to separate the glass substrate 54 or the like from the semiconductor element 51. Furthermore, the surface where the slit groove G is mechanically formed with the dicing blade is uneven, thereby causing reduction in adhesion of the glass substrate 54 and the protection film 58.